Re: performance with many columns

You provide very few clues to be able to resolve the problem Various things can go wrong
- the physical organisation of that table. If you never changed the block_size from 2048 and your recordlength is indeed 1000 (which is probably the maximum) you are storing one record block and you are likely to incur row-chaining. Analyze the suspected tables, report back the block_size, the average record length and the number of rows chained. Probably this is a substantial figure.

- are you conducting a full table scan
- if yes how large is your buffer cache
- what is the value of db_file_multiblock_read_count

As you see I'm not yet ready too believe without any further info your system is 'configured well'. This might be the case with that server, but it is a known fact the Oracle defaults where made up somewhere in the late '70s, early '80s, they never changed since and in most cases way too small nowadays. Too often sites complaining about performance problems are still using those defaults, and unjustifiedly blaming Oracle.

Hth,

--
Sybrand Bakker, Oracle DBA
Bart News <bartb_at_allinson-ross.com> wrote in message news:v37d4.1053$S64.35011_at_nnrp1.uunet.ca...
> I am having serious performance problems with Oracle when using batch
> programs (PRO*C or PRO*COBOL), that need to travers (read from
> top to bottom) fairly wide tables, i.e.
> tables with around 200 columns (table is about 1000 characters wide).
>
> I have plenty memory(1 GB), a fast, 8 CPU, UW7 machine, RAID disk, but
> compared to reading the same file in C-ISAM mode, performance is more
than
> 7 to 10 times slower. As far as I can tell, my system is configured well.
>
> Using Oracle 8 too, which allows up to 1024 columns.
>
> Any suggestions, pointers to papers ?
>
> Bart Blom
>
>
Received on Thu Jan 06 2000 - 15:24:28 CST